Turning My Roller Gate into a Smart WiFi-Controlled System

ESP32C3 Board on Proto Board

Have you ever wondered if you could take any device and control it from your phone? Well, I did! I wanted to transform my home roller gate into a WiFi-controlled system, eliminating the unreliable RF remote provided by the manufacturer.

The Problem with Manufacturer-Provided Remotes

The RF remote that came with my roller gate has been a constant source of frustration:

• Excessive Battery Drain – The remote’s battery runs out too quickly.
• Lost Programming – The remote frequently forgets its paired state.
• Manufacturer Dependency – If the remote malfunctions, I have to rely on the manufacturer to fix it.

To make things worse, the battery used in these remotes is:

• Difficult to find in Sri Lanka
• Toxic and disposable – A single-use battery with harmful compounds

Additionally, for some unknown reason, the system often loses its remote pairing, requiring reprogramming. While the controller board has a "Learn Mode", the manufacturer insists on doing the reprogramming themselves, which is both inconvenient and unnecessary.

And let’s not forget the cost—if you lose or damage a remote, replacing it costs over 3,000 rupees!

Time to Put My Electronics Degree to Work!

With all these issues piling up, I decided to take matters into my own hands. Using my background in electronics, I set out to build a WiFi-based solution that would allow me to control my roller gate from anywhere—no more unreliable remotes!

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Reverse Engineering the Gate Controller

Curious about how the gate controller worked, I decided to take apart the control board and see if I could integrate my own system. On the right side of the board, I found a green terminal block with markings for different functions:

• UP
• DOWN
• STOP

Each pin was pulled up to 12V, meaning that shorting them to ground would activate the corresponding function. This was great news! It meant I could control the gate using simple transistors.

Designing the Circuit

To interface with the controller, I designed a simple circuit that allows an ESP32-C3 to switch these functions using three 2N3904 NPN transistors. Here's the schematic:

        +12V INPUT
            │
           [LM7805]
            │
           +5V  ────────────────+
            │                   |
           GND                 GND
            │                   |
        .----------------.       |
        |  ESP32-C3      |       |
        |                |       |
        |  GPIOx ───[R]──|──B    |
        |  GPIOy ───[R]──|──B    |
        |  GPIOz ───[R]──|──B    |
        '----------------'       |
            |  |  |              |
          E |  E  E             +12V
          | |  |  |              |
         [2N3904] [2N3904] [2N3904]
          |  |  |              |
          C  C  C              |
          |  |  |              |
         (o) (o) (o)          (LOADS)
          |  |  |              |
         GND GND GND          GND
 

 

How It Works

Each 2N3904 transistor acts as a switch:

• The ESP32-C3 GPIO pins control the base (B) of each transistor through a resistor (150Ω).
• When the ESP32 outputs HIGH (3.3V), the transistor turns on, connecting the collector (C) to ground and activating the corresponding gate function.
• The emitter (E) is tied to ground to complete the circuit.

Prototyping the System

With the circuit planned out, I quickly soldered a prototype using:

• LM7805 (to step down 12V to 5V for the ESP32)
• ESP32-C3 Supermini (for WiFi control)
• 2N3904 NPN Transistors (x3)
• Various resistors (10KΩ, 150Ω)
• Electrolytic capacitors (for power stability)

This setup allowed me to control the gate wirelessly—no more dependency on the unreliable RF remote!

Setting Up the ESP32-C3 Supermini Web Server

To make the gate easily controllable from anywhere in my home, I configured the ESP32-C3 Supermini to:

✅ Connect to my local WiFi network
✅ Create its own Access Point (AP) for direct access
✅ Host a web server that serves a control interface
✅ Use mDNS so I can access it via a simple URL instead of remembering IP addresses

With this setup, I could control my gate wirelessly from my phone or computer—no more unreliable RF remotes!

Debugging a Strange ESP32-C3 Issue

During unit testing, everything worked perfectly. But once I soldered the ESP32 to the circuit and tried running the system, I was shocked—it wouldn't connect to WiFi!

I started troubleshooting:

• Was it a soldering issue? 🤔 I checked all joints—everything seemed fine.
• Was the antenna faulty? I applied pressure on the chip antenna, and suddenly, it connected! 🤨
• Re-soldering the antenna? Still no luck.
• Replacing the antenna? Same issue.

 

At this point, I needed an expert opinion. I reached out to Dilshan Jayakody, my mentor, who suggested:

💡 The issue might be WiFi power instability—the 5V rail capacitor could be too small to handle sudden power spikes when both WiFi AP and STA mode were running.

The Fix: Adding a 470µF Capacitor

I soldered a 470µF capacitor on the 5V power line to stabilize the voltage… and it worked like a charm! 🎉

With the WiFi issue solved, I completed the prototype, connected everything, and finally tested the gate control. Success! 

The Next Problem: Manual Buttons Stopped Working

Just when I thought everything was perfect, I realized that the manual control buttons on the gate weren’t working when my device was connected.

Instead of using three separate transistors, I found a 1-key operation block in the controller that cycles through:

🔼 UP → ⏹️ STOP → 🔽 DOWN

This meant I only needed one transistor to operate the gate instead of three! A simple modification, and now everything worked perfectly. ✅

---

Future Improvements

🚀 Design a dedicated PCB for a cleaner and more reliable build
⚡ Replace the LM7805 with an SMPS buck converter to reduce heat and improve efficiency
📦 Build a weatherproof enclosure to protect the circuit from the elements

This has been an exciting journey, and I want to thank Dilshan Jayakody for his guidance. Innovation is all about curiosity—so keep experimenting and stay curious!

Thank you for reading! 🙌